using -qtlibinfix result in unusable build on macos

NB: I tested the same on Windows and it works as expected, this issue is specific to macOS.

Configuring Qt with a custom -qtlibinfix doesn't work as expected on macOS.

Repro steps:

./configure -qtnamespace TestNameSpace -qtlibinfix TestSuffix -opensource -confirm-license -nomake examples -nomake tests
make module-qtbase module-qttools
sudo make module-qtbase-install_subtargets module-qttools-install_subtargets

The above build commands will build Qt with a custom libinfix (and namespace), but the libinfix makes it unusable:

• try to execute lrelease or any other tool that relies on the Qt libs, it will result in a segmentation fault. This doesn't happen if qtlibinfix is not used.
• try using the framework in Qt Creator: any inclusion of a Qt lib will fail (for instance #include <QtGui> ), as the lib won't be found. This doesn't happen if qtlibinfix is not used.

Using the exact same build commands on Windows works as expected.